Devices of this type are well known and are in particular used in brake systems making it possible to avoid a locking of the wheels in the case of heavy braking on a surface having insufficient adhesion and a spinning of the driving wheels in the case of acceleration which is too fierce to drive the vehicle.
One problem which constantly arises in the design of such systems is that which consists in preventing the relative complexity of the functions brought into play from being accompanied by a comparable complexity of the means used in order to perform these functions.